Flexible stay-bolt.



B. E. D. STAFFORD.

FLEXIBLE STAY BOLT.

APPLICATION nun APR. 1, 1914.

1,119,656, Patented Dec.1,1914.

$5.555 Mu I 5 CNVEYAIUIOR 4ffod% Unrrnn STATES PATENT ornron BENJAMIN D. STAFFORD, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO FLANNERY BOLT COMPANY, OF PITTSBURGH, PENNSYLVANIA.

FLEXIBLE STAY-BOLT.

. Specification of Letters Patent; Patented D 1 1914 Application, filed April 1, 1914. Serial No. 828,869.

To all whom elf may concern Be it known that I, BENJAMIN E. D. STAF- ronn, of Pittsburgh, in the [county ofAllegheny and State of Pennsylvania, have invented certain new and useful Improvements in Flexible Stay-Bolts; and do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the SEIHIQ.

My invention relates to an improvement in flexible stay bolts,the object being to provide means to compensate for or absorb the bendlng and tensile stress induced by the expansion of the fire box sheet, and it consists in the parts and combination of parts as will be more fully explained andpointed out in the claims.

In the accompanying drawings, Figure 1 is a view partly in elevation and partly in section of my improvement. Fig. 2 is a view in section on the line aza; of Fig. 1;

Figs. 3 and 4c are views of the spring ring bearing, and Fig. 5 is a view of a modified form.

1' represents a bolt, the underside of the head 2 of which is preferably inclined or,

conical as at '3. The underside may be rounded or curved either concave or convex, but I prefer the straight conical surface as shown. The shape and construction of the outer portions of the head are unimportant except that it should be provided with a slot or angular recess in its outer end for the attachment of a suitable driving tool.

Secured to the outer sheet 4: of the boiler is the sleeve 5 threaded externally, the bore at the inner end thereof being of greater diameter than the body of the bolt, and made flaring as shown so as to permit of a free lateral or rocking movement of the bolt within reasonable limits. This sleeve receives and houses the head 2 of the bolt, and is provided internally with an inclined seat 6 on which the spring tension ring 7 rests and moves. The outer end or face of the ring 7 is shaped to conform to the underside of the head of the bolt so that the bolt will have a solid and extended contact with and bearing on said ring, and the latter is preferably convex externally so as to have a free sliding movement on the inclined seat yield orexpand and thus permit the bolt to Y move longitudinally a distance suflicient' to compensate for the stress generated by the unequal expansion of the inner and outer v sheets of the boiler, and as thering isslidshown a bolt with ahead flat on the under side, and provided with a ring 10 of superior metal which maybe either tight or loose 'on the bolt. The outer face of the ring 10 is inclined or conical and bears, as in the preylous construction, on the correspondingly inclined face of the spring ring. The ring 10 forms in effect the underside of the head of the bolt, but by making it independent of the bolt head it can be made of superior or harder metal so as to decrease friction between the parts and better withstand the wear.

The spring ring 7 is of steel, spring tempered and maintains its normal shape and slze when the stay bolt load or tension due tov steam pressure in boiler and fire box sheets is normal. When however the inner sheet of the fire box expandsahead of the outer sheet, the stay bolt will be deflected as on lme b, 12, away from normal axis 0 0, thus putting the stay bolt under added or abnormal stress or tension due to plate ex- 'pansion. When the bolt is subjected to this added stress, the split ring expands and permits the whole bolt to move inwardly, and maintain its natural length under less stress. As the plates return to normal position the ring closes and draws the bolt back to its normal position. By this arrangement the injurious efiects on the bolt and also on the boiler sheets, caused by deflection of the bolt dueto unequal expansion, are wholly overcome, without impairing in the least the efiiciency of the device as. a-stay bolt.

It is evident that many slight changes might be resorted to in the relative arrangement of parts shown and described without departing from the spirit'and scope of my invention, hence I would have it understood that I do not wish to confine myself to the exact construction and arrangement of parts shown and described except as required by the scope of the claims.

Having fully described my invention what I claim as new and desire to secure by Lettiers-Patent, is

1. In a flexible stay bolt construction, the combination of a sleeve having a seat therein, a stay bolt, and spring support interposed between the head of the bolt and seat in the sleeve. a

In flexible stay bolt construction, the combination of a sleeve having a seat therein, a stay bolt and a split ring interposed between the head of the bolt and the seat in the sleeve.

3. In flexible stay bolt construction, the combination of a sleeve having a seat therein, a stay bolt and spring ring interposed between the stay bolt head and the seat in the sleeve, and forming a yielding seat for the bolt head.

4C. In flexible stay bolt construction, the

similarly shaped on its underside and a seat interposed between the head of the bolt and the seat in the sleeve, the said seat being adapted to contract and expand under the varying stresses to whichthe bolt may be subjected.

5. In flexible stay bolt construction the combination of a sleeve having an inclined seat, a stay bolt having a head also inclined on its under side and a split spring ring resting on the seat in the sleeve and supporting the head of the bolt. 4

6. In flexible stay bolt construction, the combination of asleeve having an inclined seat converging rearwardly, a stay bolt, the rear part of the head of which is made separate from the forward part of the head and yielding means interposed between the seat in the sleeve and the rear face of the head of I the bolt.

In testimony whereohl have signed this specification in the presence of two subscribing witnesses.

BENJAll HN E. D. STAFFORD. Witnesses:

EDWIN S. RYoE, HOWARD O. CArrnL.

Gopies of this patent maybe obtained for five cents each, by addressing the Commissioner of Eatents, Washington, D. 0. 

